Unraveling Anodic Reaction Challenges and Mitigation Strategies in Anion Exchange Membrane Water Electrolyzer (AEMWE) Systems

Enabling a nonexpensive, highly active, and durable anion exchange membrane water electrolyzer (AEMWE) promises to meet the surging energy demand reducing the carbon footprint. Their major discrepancy is the poor durability of the oxidation compartment with a less-durable catalyst and electrode-support assembly. Unlike efficient expensive catalysts IrO2 and RuO2 in proton exchange membrane water electrolyzer, the anion-exchange ones use inexpensive 3d-transition-metal-based compounds as the anode electrocatalysts. These catalysts are poorly stable at ampere-level current density, because of metal leaching, surface passivation/insulation, mechanical instability, carbon-substrate degradation, side reactions by leached metal damaging the membrane, alkaline and oxidative degradation of the ionomer, and insufficient mass transfer due to poor bubble dynamics in alkaline media. Besides efficient material design, there are various other parameters that govern the electrolyzers’ longevity. This perspective focuses on the understanding and directions to solve each above-mentioned problem to attain more stable, durable, and highly active AEMWEs.